'_FakeLoader' object has no attribute 'pin_memory_device'

[tiagu]

Hi

I am trying to run a dataloader .show_batch() but getting an attribute error:

dls.show_batch()

File env/lib/python3.10/site-packages/fastai/data/core.py:100, in TfmdDL.show_batch(self, b, max_n, ctxs, show, unique, **kwargs)
     98     old_get_idxs = self.get_idxs
     99     self.get_idxs = lambda: Inf.zeros
--> 100 if b is None: b = self.one_batch()
    101 if not show: return self._pre_show_batch(b, max_n=max_n)
    102 show_batch(*self._pre_show_batch(b, max_n=max_n), ctxs=ctxs, max_n=max_n, **kwargs)

File env/lib/python3.10/site-packages/fastai/data/load.py:137, in DataLoader.one_batch(self)
    135 def one_batch(self):
    136     if self.n is not None and len(self)==0: raise ValueError(f'This DataLoader does not contain any batches')
--> 137     with self.fake_l.no_multiproc(): res = first(self)
    138     if hasattr(self, 'it'): delattr(self, 'it')
    139     return res

File env/lib/python3.10/site-packages/fastcore/basics.py:660, in first(x, f, negate, **kwargs)
    658 x = iter(x)
    659 if f: x = filter_ex(x, f=f, negate=negate, gen=True, **kwargs)
--> 660 return next(x, None)

File env/lib/python3.10/site-packages/fastai/data/load.py:101, in DataLoader.__iter__(self)
     99 self.before_iter()
    100 self.__idxs=self.get_idxs() # called in context of main process (not workers/subprocesses)
--> 101 for b in _loaders[self.fake_l.num_workers==0](self.fake_l):
    102     if self.device is not None: b = to_device(b, self.device)
    103     yield self.after_batch(b)

File env/lib/python3.10/site-packages/torch/utils/data/dataloader.py:659, in _SingleProcessDataLoaderIter.__init__(self, loader)
    658 def __init__(self, loader):
--> 659     super().__init__(loader)
    660     assert self._timeout == 0
    661     assert self._num_workers == 0

File env/lib/python3.10/site-packages/torch/utils/data/dataloader.py:587, in _BaseDataLoaderIter.__init__(self, loader)
    583 self._rank = rank
    584 # for other backends, pin_memory_device need to set. if not set
    585 # default behaviour is CUDA device. if pin_memory_device is selected
    586 # and pin_memory is not set, the default behaviour false.
--> 587 if (len(loader.pin_memory_device) == 0):
    588     self._pin_memory = loader.pin_memory and torch.cuda.is_available()
    589     self._pin_memory_device = None

AttributeError: '_FakeLoader' object has no attribute 'pin_memory_device'

Any idea of how to solve this?

Thank you

---

torch 2.1.1
fastai 2.1.10
torchvision 0.16.1
fastcore 1.5.29

cuda available: True, 12.1